UFO performed Coldplay’s "Yellow" and made it through on "Space Night."
Lamp was revealed to be actress Melissa Joan Hart after a clumsy unmasking moment.
Hart said she appeared on the show to overcome her fear of singing in front of people.
Alicia Witt, who was behind the Dandelion mask, was the winner of last week’s episode.
Ken Jeong correctly guessed Witt's identity.
Witt is an actress, singer, and songwriter who has appeared in TV's "Nashville" and David Lynch's "Dune" film and "Twin Peaks" series.
This season's unmasked celebrities also include George Wendt, Christine Quinn, Holly Robinson Peete, Alexa Bliss, Malin Akerman, Lele Pons, Michael Bolton, Grandmaster Flash, Debbie Gibson, Howie Mandel, Sara Evans, and Dick Van D***.
Witt said appearing on "The Masked Singer" was one of the best experiences of her whole life.
"The Masked Singer" is a popular, wacky hit show on Fox.